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Old Nov 20, 2014, 02:15 PM
Aurora Builder
United States, MD, Lusby
Joined Nov 2003
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Originally Posted by elkski View Post
Sam, what do you fly?
Elkski,

I fly my own stuff usually, Auroras. My own ZV2 wing design, actually lower aspect ratio than most (aurora is AR=10.0, reference ZV2 is 10.5, most designs are pushing 11-12). Hollow molded but tooling up for solid core molded. I like to fly other designs when I can to see the performance
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Old Dec 05, 2014, 07:23 PM
ET
eteet's Avatar
United States, DE, Hockessin
Joined Apr 2006
700 Posts
Fyi...

I got a little paranoid about my 1S setup in the XX Lite so I decided to check it out. I charged the battery and set the transmitter to cycle all of the control surfaces at a rate one full sweep every second. After 48 minutes the JR 285s on the flaps stopped working but the Airtronics 90802s on the R/E kept going. The ending voltage on the battery was 3.2v and it took 566 mAh (out of a total of 600) to recharge it. This was at room temperature.

So I feel comfortable flying for a half hour. Hope I’m right.

Eric
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Last edited by eteet; Dec 05, 2014 at 09:41 PM.
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Old Dec 05, 2014, 08:00 PM
2013 US F3K Team Manager(ret)
Newbury Park, CA
Joined May 2005
1,053 Posts
Quote:
Originally Posted by eteet View Post
I got a little paranoid about my 1S setup in the XX Lite so I decided to check it out. I charged the battery and set the transmitter to cycle all of the control surfaces at a rate one full sweep every second. After 48 minutes the JR 285s on the flaps stopped working but the Airtronics 90802s on the R/E kept going. The ending voltage on the battery was 3.2v and it took 566 mAh (out of a total of 600) to recharge it. This was a room temperature.

So I feel comfortable flying for a half hour. Hope Im right.

Eric
You are being way too conservative..

So the load you were putting on it was approximately 707 mA/h (566*60/48). Realistic load of a typical DLG in flight is less that 200mA/h.

I fly with a 1S 500mAh pack and have a rule to stop flying it after 1 hour; Voltage is 3.7 and typically I put about 180 mAh back in on charge. I should be able to fly for 2 hours and still have a decent safety margin.

(This is on an XXLite w/MKS65k's on aileron and d-47 on E/R)
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Old Dec 05, 2014, 08:13 PM
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San Diego
Joined Aug 2004
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Lex,

Don't forget that if he is using a telemetry RX, the power consumption will be higher. Also, those servos are likely more power hungry than what you are using. So while I agree he is being conservative, charging after 30 minutes wouldn't be a bad idea. Then again, if he is using telemetry, he should know what the RX voltage is so there shouldn't be any surprises. One of the nice things about LiPo compared to LiFe is the steady voltage drop. I'd consider charging once you reach around 3.6 volts just to be safe.

If you don't have telemetry, I would suggest monitoring your battery voltage every 5 or 10 minutes the first time you go out so you have real world numbers for your actual usage.

Tom
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Old Dec 05, 2014, 09:35 PM
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eteet's Avatar
United States, DE, Hockessin
Joined Apr 2006
700 Posts
I am being conservative but then again I'm betting a $1000 plane on a $3 battery. The spring/string has got me spooked and I don't have a good idea of the power requirement for this kind of setup. The charged voltage for my battery was 4.2 and the voltage when the 285s stopped working was 3.2 volts. That's one whole volt to play with. Scary.

After I get some experience with flying for 30 minutes I'll see about increasing my flight time. It takes so little time to swap out the battery that it's not much of an inconvenience to change it.

I'm using a telemetry rx but I'm not using any modules. It's a FrSky rx and it has the RSSI feature which does use some power.

Eric
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Old Dec 05, 2014, 10:43 PM
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United States, SC, Mt Pleasant
Joined Jan 2013
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I'm no expert, but I think you're both right. dlgdude is right in that Eric is probably being too conservative and could probably fly longer without a problem. But if I was Eric, I'd err on the side of saving my XX rather than chancing a battery failure. FWIW, I fly all three of my Helios2's and my Helios 1 (all spring/string) on 1S 600's and am totally comfortable with an hour of flight time. Even then, I usually only have to put back in less than 300mah.
Hope this helps
Paul
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Old Dec 05, 2014, 11:33 PM
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San Diego
Joined Aug 2004
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Just out of curiosity I looked up the power consumption for the FrSky RXes. Non telemetry is 30 mA. Depending on which telemetry RX, consumption is either 60 mA or 100 mA.
Not sure what the consumption is for an Airtronics FHSS-3 RX, but I would guess it is closer to the 30 mA level.

So it wouldn't surprise me at all if Eric's setup consumes 300 mAh or maybe higher in actual use. Still should be good for an hour safely, but certainly worth keeping an eye on.

Tom
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Old Dec 06, 2014, 10:32 AM
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Joined Aug 2009
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the weather and the type of flying has a great deal in power consumption too.

flying for fun in nice weahter or doing launch/land/ launch/ land in windy conditions (like doing 5x2's in a contest ) is a big diffrence pulling brakes at high speed or high wind does eat battery.

also the d47 should use way less on pull spring then a digital like the ds09 on the same setup...

set your timer low and learn how much it takes to recharge it in various conditions , you can always fly longer once you notice you there's a big margin
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Old Dec 06, 2014, 11:24 AM
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United States, DE, Hockessin
Joined Apr 2006
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Quote:
Originally Posted by krikkens View Post
you can always fly longer once you notice you there's a big margin
That's the plan.
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Old Dec 06, 2014, 04:33 PM
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United States, UT, American Fork
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Mmmmmmmmmmmmmmmmmmmmmmmmmmm, spent all morning putting the XXL up against some very nice ships, against a pretty good pilot here in the US, and well, the XXL did just fine!
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